Arthur Andersen once was one of the world's largest accountancy firms.

But now a jury in a US court has found the firm guilty of obstructing justice by shredding documents relating to the collapse of energy giant Enron, one of its audit clients.

BBC News Online explains the impact of the verdict.

What now for Andersen?

Andersen says it is likely to appeal, once it knows how severe the penalty is. The judge, Melinda Harmon, will hand down her sentence on 11 October.

But any victory in the courts would come too late, because as a company Andersen is more or less finished.

The auditing of company accounts - checking whether they are truthful - has been the mainstay of Andersen's business.

Andersen audited the books of energy giant Enron, but when the firm collapsed amid accusations of accounting irregularities, the auditor was deemed not only to have failed in its job, but to have shredded thousands of potentially incriminating documents relating to the case as well.

Many of Andersen's high-profile audit clients, fearing that association with the accountant could taint them in the eyes of their own shareholders, took their business elsewhere.

Many Enron investors are also demanding that Andersen compensate them for the damage done at Enron. If their lawsuits are successful, they could bankrupt what remains of the company.

If the firm survives at all, it will be a much smaller operation, with just a few thousand staff.

What's currently left of Andersen?

Not much.

The company that was convicted by the jury in Houston, Texas, is Arthur Andersen LLP, the US arm of Andersen Worldwide. Globally, Andersen once had more than 85,000 employees.

But during the past six months, the regional Andersen partnerships in 83 countries have all decided to abandon their colleagues in the US, and merge with rival companies.

The US part of Andersen has been busy disintegrating as well. It used to employ 28,000 people, but less than 10,000 are left now.

Andersen's tax experts, for example, have joined Deloitte & Touche, while its IT consultancy is likely to be taken over by rival accounting firm KPMG.

Arthur Andersen's core business of auditing publicly listed companies is also severely dented. Already more than 700 companies have dumped Andersen, about a third of its customer base.

And now Andersen itself has thrown in the towel, saying it will close down its business of auditing publicly listed companies by September.

This, however, is more of a pre-emptive strike than an act of remorse. Following Andersen's conviction, the US stockmarket watchdog - the Securities and Exchange Commission - would have banned Andersen from auditing publicly quoted companies anyway.

Tough luck for Andersen - but why should I care?

The impact of Andersen's troubles will be felt far beyond the company's own staff and its clients.

The accounting scandal at Enron and Andersen - closely followed by allegations of irregularities at a string of other firms including WorldCom, Tyco and Adelphia - have undermined investor confidence in corporate America.

The collapse of investor trust in corporate accounts, which are used to project future profits, has had a knock-on effect of share prices.

Stockmarkets have been hit hard - not only on Wall Street, but around the world.

Share prices are currently highly volatile, but the underlying trend is firmly downwards.

If you have a pension, a life insurance policy, or an endowment mortgage, it is likely that you will be affected. Even your job could be at risk.

The market turmoil is also undermining the global economic recovery, depressing employment and earnings prospects for everyone.

Uh oh. What about Enron? I thought they caused the whole mess.

Enron is still in the dock. Most of its assets have been sold off, and what remains of the company is still under investigation - both by the US Justice Department and by Congress.

The company is also facing potentially ruinous lawsuits from aggrieved investors and former employees, many of whom lost their retirement savings in the Enron bankruptcy.

Questions are also being asked about links between the US government and Enron, which was a major contributor to President George W Bush's 2000 presidential campaign.

Earlier this month, the White House agreed to give Congressional investigators documents relating to the White House's contacts with Enron, but held out for an undertaking that their full contents would not be made public.